I need help to decide to install a larger capacity gas water heater or consider a tankless system.please give the pros and cons.
Thanks,Jim

A lot depends on the needs. What is the situation?
In general, people are moving towards instant on water heaters for cost efficiency, but they may not provide enough hot water to several users at any given moment. Only you can weigh the luxury of using 50 or more gallons of hot water all at once and then letting it make 50 more gallons that might just sit there cooling off and being reheated over and over, versus planning use in sequence. The sequential use, of course, is unlimited. So it makes good sense.

We added a tankless water heater last year. There are 7 people in my house so we go through a lot of water! I do like the fact that we never run out of hot water. I was hoping that it would be instant hot water but we do have to run it for a bit before the hot water comes out. It may be due to the distance from the tank… ( I am not a plumber so I don't know). We also do have a pressure issue in the shower if other items are in use (toilet, washer…). Again, someone told us that this has nothing to do with the tankless unit, but I thought I'd mention it. Overall, we do like the tankless unit. I love that it freed up more space in my work room. Savings… have not noticed much of a change. Some say that you save because you are only heating was as it is needed - and others say that the BTU that are needed to heat that water are so high that they end up being as expensive as the regular floor units (?). Good luck!

Pro, limitless hot water. Con, price. A good sized tankless unit will run you about $1300, just materials, compared to a tank heater for $300-400. Can you install tankless on your own, not as easy as a tank heater at all.

They try to make them a good sell but for many people, their wiring isn't sufficient or they need to increase the gas line size , costing +++$, along with the 2X+ cost over a tank type. I'd still go with a well insulated 50 gal gas or electric. Make sure all exposed pipes are insulated too.

Start up cost is much higher. Also, not every house is suitable for tankless. Call couple of certified tankless hot water heater installers and ask them for their opinion. Find such leads in your area on manufacturer's web sites, like for Rinnai Tankless water heaters: (Tankless Water Heater Buyer's Guide & Local Dealer Search | Rinnai America (http://www.foreverhotwater.com)) etc. Good luck... Let us know what you've decided to do... Back to you... Milo

Con: In the event of a power outage, the tankless unit will not provide hot water. A gas-fired storage-type unit will not be affected (unless it is a power-vented type), and an electric storage-type unit will still maintain what is stored for a while.

KC13: you can install power back up. With power back up installed, you can use Tankless Water Heater even during power outage.

Milo is right but for me, when the power is out, I don't have much of a call for hot water. Washing machine and dishwasher won't be working, lights in the bathroom are out, etc...

I have FHW with tankless off the boiler, and ideal for me (cheapest) would be one that didn't calcify so fast, or that was cheap to replace, and a regular 40 gallon tank for summer, to save on oil.

I have a solar hot water heater. I have an 80 gallon Rheem electric hot water tank that NEVER runs out of water. The temperature of the water at any given time is anywhere from 110° to 160° F, usually between 120° and 140°. I have turned the breaker on for one month this winter when we had a lot of non-solar days. I received a 30% rebate on the cost of the system on my taxes this year.

KenSayers, where do you live?

I live in North Florida. BUT, external temperature is not the issue as much as the number of solar days. The rebate was Federal. The system cost $5,000, but $3,500 after rebate. Were I to buy the water heater without solar, the water heater itself would cost over $1,000. It increases the resale value of the house and dramatically decreases your utility bill. Along with a few other green considerations and a 2.1 kW photovoltaic system, my all electric house cost less to operate for an entire year than what my friend in NJ spends on one of several fuel oil deliveries.